SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9437988a69665c7284c0c9677a10d21d5d224fb538af736a04f5c7c7e12b19a9' 
  AND token = 'qjtX+rXj1aykZdTteNLfdjoCA//o9MXdJSl7qTeI2fQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}